Eclipse Spyder FWD L4-2350cc 2.4L SOHC 16 Valve (1996)
Heated Oxygen Sensor: Description and Operation
PURPOSE/OPERATION
The oxygen (O2) sensors provide feedback to the engine control module about combustion efficiency. The system operates by measuring the
oxygen content of exhaust gases. The sensors are equipped with a heater element which helps the sensors reach operating temperature faster. The
oxygen sensors are made of a ceramic material called zirconium dioxide. The inner and outer surfaces of the ceramic material are coated with a
very thin layer of platinum. The outer surface is exposed to exhaust gasses, while the inner surface is exposed to outside air. The difference in the
amount of oxygen contacting the inner and outer surfaces of the oxygen sensor creates a pressure differential which results in a Voltage signal
being generated. The amount of Voltage produced is determined by combustion efficiency. Voltage output from the oxygen sensor can reach 0.9
Volts DC when the fuel air mixture is too rich and about 0.1 Volts DC when the mixture is too lean, with a sharp Voltage transition from high to
low at the stoichiometric point. The engine control module's instant mixture adjustment in response to the Voltage output of the oxygen sensor
causes the output Voltage from the oxygen sensor to fluctuate rapidly between 0.1 and 0.9 Volts DC and will be observed as an average of about
0.6 Volts DC when measured with a Voltmeter.
